A doctor told Carrie Chilvers, 28, from Colchester, there was only a one in five chance that her baby would survive when she had her three-month scan at Colchester General Hospital, Essex.
She was told even if her baby did survive, he or she would have Down's syndrome, Turner's syndrome or a chromosome deficiency.
Carrie refused to give up on her unborn child but had to endure five weeks of anxiety as she refused to have an immediate termination without a second opinion.
She had a second scan five weeks later and was told her growing baby was perfectly healthy. She gave birth to Elizabeth, who weighed 5lb, 4oz, in January.
Colchester General Hospital has apologised for the blunder and says the clinician who misdiagnosed Carrie no longer works for them.
"If I had listened to them I would not have my beautiful baby girl," says Carrie. "If I had a termination Elizabeth would not be here and my six-year-old son Conna would not have the little sister he wanted.
"I was told three times to have an abortion. They said there was only a 20 per cent chance when I gave birth she would still be alive and she had a cystic hygroma, a growth on the neck."
"They did not tell me anything. They gave me no help or information. It was the worst five weeks of my life. It was like having a ticking time bomb inside me knowing her heart might just stop. I was crying all the time and was off work for weeks."
Instead of following the doctor's advice, Carrie did her own research. She went to see another consultant who agreed she should see Professor Khaled Khaled, who realised his colleague had made an error.
"Professor Khaled was brilliant and I cannot fault him. He told me there was nothing wrong."
Carrie complained to the hospital and she had now received a letter telling her the clinician who misread the scan no longer works there. In the letter, the hospital claims it told Carrie there was a 50/50 chance of an abnormality and disagree on the chances of a miscarriage.
A spokesman for Colchester General Hospital said: "We are grateful for Miss Chilvers' kind comments about Professor Khaled but are sorry she was disappointed with some aspects of her care.
"We carried out a detailed investigation after she made a formal complaint. The complaint was partly, but not wholly, upheld.
"Where appropriate the trust has apologised to Miss Chilvers and, in addition, an individual clinician has apologised to her in writing. In a letter to her we addressed in detail her outstanding concerns and, again, have apologised where appropriate."